Docs: Update Latest Quickstart to Match Release Quickstart

[danehans]

#1673 updates the steps in the released vesion of the quickstart guide. The same updates should be implemented in the site-src/guides/getting-started-latest.md guide.

[danehans]

Add a hidden note at the top of both quickstart guides stating that the other quickstart should be updated if this file is changed.

[danehans]

Note that #1747 updates Kgateway in the latest/main quickstart guide.

[dharaneeshvrd]

/assign